EHD-enhanced convective boiling of R-134a in grooved channels: Application to compact heat exchangers
- Univ. of Maryland, College Park, MD (United States)
Electrohydrodynamically (EHD) enhanced flow boiling of refrigerant R-134a inside grooved channels of approximately 1mm hydraulic diameter was investigated with the objective of addressing the applicability of the EHD technique in highly compact heat exchangers. Two sets of experiments were performed. The first set included experiments in a channel with a smooth heat transfer wall whereas in the second set the heat transfer wall represented one of the commercially available enhanced microfin tube surfaces. In each case experiments were conducted as a function of the applied electrical field strength, electric field polarity, flow Reynolds number, average test section vapor quality, and flow direction (upward, downward or horizontal). It is demonstrated that in all cases the EHD effect can substantially increase the heat transfer coefficients particularly at low Reynolds numbers and when applied over the enhanced (microfin) geometry. The field polarity is seen to have little influence on the enhancement process.
- OSTI ID:
- 455378
- Report Number(s):
- CONF-951135--; ISBN 0-7918-1754-7
- Country of Publication:
- United States
- Language:
- English
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